Misfiring or the like frequently occurs in the case of manually operated starters as a result of generally known, undesired circumstances in the engine to be started, and continue as kick-backs to the elements of the starter which are actuated manually by the operator. In the case of starters for low-power internal combustion engines, such as engines used on lawnmowers, these kick-backs rarely lead to any serious incidents, such as injury to the operator. However, in the case of larger engines, a strong kick-back may lead to serious injury to the operator's hand or even to bodily injury if the operator is pulled violently against the walls of the machine itself or against the units carrier thereby as a result of an abrupt, violent kick-back on the operating cord of the starter.
For the purpose to avoid disadvantages of this kind, a safety means is provided in the known starters and, in the event of an unsuccessful starting operation and upon kick-back of the engine element to be started against the starting direction, said safety means uncouples the actuating means of the starter from the back-kicking engine element.
It is an object of the present invention to develop a safety means having a simple construction and a secured operation. In accordance with the invention, the starter is equipped with a driven member which is rigidly seated on the engine element to be started, and with a driving member which, during starting, is driven by way of an actuating means in the form of a pulley having a cord and pull handle for the cord and drives the engine element in the starting direction, and the safety means is in the form of a fixedly mounted, spring-loaded decoupler pawl which does not affect the driving engagement between the driven member and the manually operated driving member when the starter elements are in their resting positions and during their starting movement, whereas, upon kick-back of the engine element to be cranked, the pawl is brought into the decoupling position by means of an element which then kicks back, and thereby releases the driving engagement.
It is advantageous if the driven member comprises a cup-shaped bell whose periphery is provided with a plurality of openings, and if the driving member comprises a spring-loaded drive pawl mounted on the pulley and is adapted to engage by means of its drive nose into one of the openings under spring force and carries along the driven member during the starting movement, and if the decoupling pawl is held by its spring in its remote position outside the range of movement of the driven member during the starting movement whereas, upon a kick-back movement, the decoupling pawl is brought by the back-kicking driven member into engagement in one of the openings and pivots the drive pawl out of the opening and into a position outside the range of movement of the driven member, whereby the driving engagement between the driven member and the drive pawl momentarily kicking back with the pulley is released.
Furthermore, the arrangement may be designed in such a way that the decoupling pawl is a one-armed pawl, whose associated spring seeks to urge it into a remote position outside the range of movement of the driven member and against a resilient stop.
It is also advantageous to construct the arrangement in such a way that, at least when the starter elements are in their normal resting positions, the drive nose of the driving pawl projects through one of the openings into the region outside the driven member where drive nose co-operates with the decoupler nose of the decoupler pawl.